I'm feel awful for all three of you. That sounds like an incredibly stressful situation, and you're clearly not a bad dog owner.

So obviously there's more going on than anything you're doing. But I would absolutely stop giving her bones. They may be her favorite thing, but they also cause her a lot of anxiety trying to protect that thing. Overall, I think it's best to stop. It won't stop her aggression, but it will get rid of one situation that you know will cause her to act aggressively.

Is she crate trained? This is one of my more straight-up-crazy-dog-lady moments, but when I had a foster who was unpredictably aggressive towards my own dog, I kept them separated 100% of the time until I got a takeover for her. But she was so sad not to be in bed with us that I just put her crate on my bed so she could sleep with us (she was fine being near my dog when one of them were in the kennel, but when there wasn't a barrier she'd freak out).

But most importantly, DEFINITELY talk to a vet about this. Document each incident for a period with dates and times so they can see the full extent objectively without trying to figure out if you're under/over describing the problem.

It's possible there's something neurologically wrong (either from poor breeding or previous abuse) that unfortunately may not be fixable. It's also possible that she's a candidate for dog Prozac, which works very well for some dogs (but takes a month or more to really start to work). Good luck!